在屏幕上开三个窗口，按→键进入右窗口输入字符，并在下窗口显示。按←键进入左窗口输入字符，并在下窗口显示。屏满卷屏。-On the screen to open the three windows, press → key to enter characters into the right window, and the next window displays. By ← keys to enter characters into the left window and the next wi